Iran's Islamic Revolutionary Guards Corps (IRGC) says it was behind a rocket assault on an Iranian Kurdish rebel group in Iraq that killed at least 11 people.

In a September 9 statement carried by Iran's semiofficial Fars news agency, the IRGC said it fired seven missiles in the attack a day earlier on the armed opposition group in northern Iraq.

"In a successful operation, the Guards' aerospace unit, along with the army's drone unit...targeted a criminal group's meeting and a terrorist training center with seven short-range surface-to-surface missiles," the statement said.

The Kurdistan Democratic Party of Iran (KDPI) told the AFP news agency on September 8 that its organization was holding a meeting at the time of the attack.

"Eleven KDPI members were killed and 30 wounded by Katyusha rockets fired on their headquarters in Koysinjaq," Kamran Abbas, director of the city's hospital, told AFP.

"Iran used long-range missiles in a coordinated attack on [KDPI] bases and adjacent refugee camps," the group said on Twitter.

The KDPI occasionally carries out attacks inside Iran from its bases in Iraq and is listed as a "terrorist" group by Tehran. Several of its leaders have been killed in attacks the group has blamed on Iran.

The group is an armed leftist party made up of ethnic Kurds from Iran. It has been based in northern Iraq after it was banned in Iran.

It conducted a guerrilla war against Iranian forces from 1979 to 1996, when it declared a cease-fire. In 2016, it announced it would resume armed resistance.

The Kurdistan regional government -- the Irbil-based and Western-backed government of the autonomous region in Iraq -- condemned the attack, saying it violated Kurdish law and territorial integrity

"We reiterate our rejection of using the Kurdistan region's land to attack neighboring states, which is in no way acceptable and can lead to instability in the Kurdistan region," it said in a statement.

Millions of ethnic Kurds live in the mountainous region along the borders of Turkey, Iraq, Syria, and Iran.

Some have links to Turkey's militant Kurdistan Workers Party (PKK), which has for decades fought for an independent homeland.